Drug interactions
Cyclizine + Promethazine
Severity: Moderate
Cyclizine and Promethazine: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both are sedating antihistamine antiemetics with anticholinergic effects, so the combination duplicates therapy and increases drowsiness, dry mouth, urinary retention and confusion.
What this interaction means in plain words
Cyclizine and Promethazine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Cyclizine belongs to Respiratory; Promethazine belongs to Respiratory.
Why it happens
Additive H1 receptor and muscarinic receptor blockade.
What to do
Avoid combining two antihistamine antiemetics and choose a single agent or a different class. Monitor for sedation and anticholinergic effects if overlap occurs.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Promethazine
- Cabergoline + Promethazine Contraindicated
- Dopamine + Promethazine Contraindicated
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
Other interactions of Cyclizine
- Calcium / magnesium / potassium / sodium oxybates + Cyclizine Major
- Cyclizine + Henbane Major
- Cyclizine + Sodium oxybate Major
- Abobotulinumtoxina + Cyclizine Moderate
- Alfentanil + Cyclizine Moderate
- Alprazolam + Cyclizine Moderate
Frequently asked questions
Can I take Cyclizine with Promethazine?
MediHelp rates the interaction as moderate. Cyclizine and Promethazine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both are sedating antihistamine antiemetics with anticholinergic effects, so the combination duplicates therapy and increases drowsiness, dry mouth, urinary retention and confusion.
How serious is the interaction between Cyclizine and Promethazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combining two antihistamine antiemetics and choose a single agent or a different class. Monitor for sedation and anticholinergic effects if overlap occurs.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Cabergoline, Dopamine, Ibutilide. The full list is on the Promethazine page.
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